The present invention relates to an apparatus used in helping penetrate earthen formations, especially subsea soils as encountered in offshore wells, when used in combination with conductor pipe section as such are known in the drilling of wells for hydrocarbons and other fluids.
It is known, in the drilling of wells for hydrocarbons and other fluids, to drive conductor pipe or tubulars, comprising a string of segments of large diameter tubulars such as conductor pipe, into an earthen formation, especially offshore into the seabed.
As is known in the art, a well bore into an earthen formation provides a cylindrical, continuous casing for drilling of the well. In current practice, conductor pipe is driven from a point below a drilling rig floor to form a continuous string to a point in the earthen formation anywhere to a desired depth. This string of conductor pipe is normally driven by a pile driving apparatus such as a pile driving hammer. The conductor pipe string should be driven in as straight a line as possible since typically the center line of the conductor pipe should be the center line of the well bore for guiding and directing subsequent casing and drilling operations.
A procedure used for driving conductor pipe depends upon numerous factors such as hardness of the earthen formations and the friction on the inner and outer circumference of the pipe which cause increasing resistence to penetration as a conductor pipe is driven into the soil.
U.S. Pat. No. 4,657,441 teaches that soil is compressed and that such compression of the soil is unacceptable when using a drive shoe. The soil is compressed because, as the pipe is driven, both the soil at the inner diameter (ID) of the drive shoe and the soil at the outer (OD) of the shoe are compressed. U.S. Pat. No. 4,657,441 teaches breaking up of the soil by having a series of ribs and a series of spiral inner bar sections on the OD to torsionally disassociate the soil, intermittently de-cohering the soil causing it to break up and become loose.
An object of this invention to provide an improved drive shoe for use in pile driving surface conductors.
Another object of this invention to provide one or more earth formation structures mountable on the pilings to be driven.
Another object of the invention is to provide a drive shoe with a serrated leading edge with all other surfaces inclined to move the formation away from the drive shoe and following tubular structures to reduce the drag of the formation on the surfaces of the driven piling.
These and other objectives, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims. However, it will be understood that above-listed objectives and/or advantages of the invention are intended only as an aid in understanding aspects of the invention, are not intended to limit the invention in any way, and therefore do not form a comprehensive or restrictive list of objectives, and/or features, and/or advantages.
Accordingly, the invention comprises, in one embodiment thereof, a piling assembly to facilitate pile driving a piling into the surface of an earthen formations. The assembly may comprise one or more elements such as, for instance, a plurality of surface conductors comprising an inner conductor surface and an outer conductor surface, a drive shoe having a first end attachable to the plurality of surface conductors and a second end for engaging the earthen formation, and/or at least one conductor earth formation displacing structure for compressing the earthen formation. The conductor earth formation displacing structure may be mounted directly to at least one of the inner conductor surface or the outer conductor surface. The earth formation displacing structure is operable for compressing the earthen formation away from the at least one of the conductor outer surface or the conductor inner surface for enabling enhanced penetration of the plurality of surface conductors into the earthen formation.
The piling assembly may further comprise a collar mountable to the outer conductor surface. In one embodiment, the collar further comprises a first connecting end for connecting to a first of the plurality of surface conductors, and a second connecting end for connecting to a second of the plurality of surface conductors thus forming a joint of the surface conductors. In another embodiment, the collar further comprises an inner surface of the collar mountable between the conductor first end and the conductor second end.
In another embodiment, the invention comprises at least one piling earth formation displacing structure mountable to the outer surface of the surface conductors to extend radially outwardly for compressing the earthen formation during the pile driving.
In another embodiment, the invention comprises a drive shoe with a plurality of different conical surfaces formed therein.
In another embodiment, the invention comprises one or more elements such as, for instance, a tubular body with first and second ends and having an inside diameter smaller and an outside diameter larger than those dimensions for the piling to be driven into the earthen formation, a first conical surface inside the tubular body and opening toward the first end and intersecting an outside surface of the tubular body to define the first end, and/or a plurality of grooves beginning axially outside of or above the first conical surface and cutting into the tubular body and continuing toward the first end to cut into the first conical surface to form a cutting edge at the first end for cutting into the earthen formation.
The grooves may be cut such that surface lines produced are at least forty-five degrees with respect to a flat plane orthogonal to a centerline of the tubular body. In one embodiment, the cutting edge is blunted in a radial dimension thereof ranging in width from one-eighth inch to one-quarter inch. In one embodiment, the invention further comprises a plurality of collars with a diameter approximately the same as the outer diameter of the tubular body such that the plurality of collars being provided at respective joints of the tubular pilings.
A new and improved drive shoe for penetrating the soil is disclosed. The drive shoe, typically fastened below a conductor pipe section, has been found to increase the driveability of a string of conductor pipe by causing soil to be compressed and moved away from the ID and OD of the drive shoe. Moving the soil away from the ID and OD of the drive shoe reduces surface friction on the drive shoe.
In one preferred embodiment, the invention includes a drive shoe that is larger than the conductor pipe and connected to the bottom section of the conductor pipe, and teeth, extending from and forming the bottom of the drive shoe to enhance penetration. In this preferred embodiment, the teeth are formed by first cutting a beveled section from the bottom of the drive shoe where the bevel angles from the OD to the ID of the drive shoe. The teeth are then formed in the beveled bottom such that the interior of the beveled angle causes a compression of the earthen formation away from the ID of the drive shoe.
In an alternative embodiment, the invention may comprise a drive shoe having a larger size OD than the outer diameter of the conductor pipe to which it is attached where the drive shoe is connected to the bottom section of the conductor pipe, and an exterior band that is mounted on or otherwise part of the OD of the drive shoe without the necessity for teeth.
In yet a further alternative embodiment, the invention may comprise a drive shoe having a larger size ID than the inner diameter of the conductor pipe to which it is attached where the drive shoe is connected to the bottom section of the conductor pipe and an interior band that is mounted on or otherwise part of the ID of the drive shoe without the necessity for teeth.
In any embodiment, the drive shoe may further comprise one or more inner bands mounted on or otherwise part of the drive shoe ID to further compress the soil away from the interior surface of the drive shoe. Further, the drive shoe may also have one or more outer bands one or more mounted on or otherwise part of the drive shoe OD to further compress the soil away from the exterior surface of the drive shoe.
This summary is not intended to be a limitation with respect to the features of the invention as claimed, and this and other objects can be more readily observed and understood in the detailed description of the preferred embodiment and in the claims.